1. Field of the Invention
The present invention relates to a grip structure in which a grip is provided in a grip portion of a writing implement.
2. Description of the Related Art
A writing implement, which includes a coating implement such as a so-called correction pen having a similar structure to the writing implement not for the purpose of writing, is often used in daily living when writing characters and drawing pictures. It is frequently used for a long time. The ease of gripping the writing implement (grip feeling) and the degree of fatigue caused by writing depend mainly on its grip structure. Generally, the softer the grip is and the larger the contact area between fingers and the grip is, the better the grip feeling becomes. In the case, the effect of decreasing fatigue is achieved because the gripping pressure is properly dispersed. Therefore, regarding the grip structure provided in the grip portion of a barrel of the writing implement, various structures have so far been proposed.
The present applicant has proposed in Japanese Patent No. 3024731 a writing implement which comprises an outer coat made of flexible material fitted around a barrel so as to form a space between the outer coat and the outer surface of the barrel and, a liquid substance which is filled in the space between the outer coat and the outer surface of the barrel with fluidity at a normal temperature, and a grip portion constructed on the surface of the outer coat.
Certainly, by filling the liquid substance in the grip portion, the hardness of the grip portion can be decreased. Therefore, when gripping the grip, the grip portion can easily be deformed according to the degree of gripping, by which the contact area between the fingers and the grip portion increases and thus the gripping pressure is distributed. As a result, the grip feeling is improved, and fatigue caused by long use is decreased.
However, the way of gripping the writing implement and the gripping force differ between individuals. Therefore, when a user having strong gripping force grips the grip portion filled with the liquid substance having fluidity, the liquid substance flows from the portion where the user actually grips to a portion with no gripping pressure applied, and thus there seldom exists the liquid substance in the portion with gripping pressure applied. Accordingly, the fingers often feel the hardness of metal or resin material forming the barrel located inside of the liquid substance, so that the grip feeling is rather impaired.
Moreover, the outer coat is sometimes damaged by mistake and thereby a pore or crack is made, resulting that the liquid substance filled within leaks from the pore or crack to obstruct the use of the writing implement.